1. Field of the Invention
The present invention relates to aircraft surface guidance systems (SGS) and, in particular, to a method to format and store data regarding the paved surfaces, gates, and buildings of an airport and to display a map of the airport to the pilot.
2. Technical Background
There is considerable interest in enhancing the field of surface guidance for aircraft. After an aircraft lands at an airport the next step is to taxi the aircraft to a desired destination such as a passenger loading/unloading gate. A pilot can become confused or lost amid the many runways, taxiways, ramps, and buildings. The problem is more significant at large airports and is particularly significant at night or in low visibility conditions when the multitude of lights can make it more difficult to taxi to the desired destination.
Efficient taxi operations save time and money. Airports are becoming more crowded. Aircraft often spend considerable time taxiing between runways and gates. Taxi time is even longer if a pilot makes a wrong turn, becomes lost, or blunders onto the wrong runway or taxiway. In addition, a wrong turn or navigation blunder can cause delays for other aircraft at the airport.
A main feature of an airport surface guidance capability is the presentation of an airport map that is readily available to the pilot. One way to present such a map is on a head-down display (HDD) that is in the forward field of view of the pilot. The pilot identifies the aircraft's current position of the aircraft on the map and the destination location and is able to quickly understand the approved taxi route provided by ground controllers. The airport map may also indicate the current aircraft position and a selected taxi route overlaid on the airport map. The map gives a pilot situational awareness of the aircraft's position relative to the destination and the taxi instructions.
An obstacle for the practical implementation of an avionics systems to aid the pilot in finding his way safely to the active takeoff runway or, conversely, to the gate after landing, is the requirement to clearly display an airport map, preferably with taxi instructions and current aircraft position overlaid on the map. Prior avionics systems have attempted to display airport maps by storing the airport map as a digital picture. While this approach works, representation of the airport map in this manner requires large amounts of memory for each airport. An airport map of a single airport can consume more than one gigabyte of memory. This requirement, coupled with the fact many avionics systems have limited data storage capability, have stymied efforts to implement airport maps on many aircraft. Another approach for displaying airport maps has been to upgrade aircraft avionics systems with new equipment that has large data storage capability. However, these systems must be designed, certified, integrated with the existing avionics suite, and installed. All this makes such an upgrade very costly and, therefore, this approach is economically infeasible for many aircraft.
It is generally desirable for an aircraft taxi planning and map system not only to accomplish the tasks of storing and displaying airport maps, but to also make the implementation cost-effective. The continuing goal, therefore, is to find ways to reduce costs, reduce taxi errors, save taxi time, and improve airport efficiency.